Hi @Summer1 . Currently, we have 4 different content-types3 available in all communities. You can enable/disable any of these types and you can rename them to anything you want. For example, you can enable the "Article" content type and change its name to "AMA". Also, you can choose who can post this type of content (only admin, moderator, or all users). You can learn more about the settings here3.
FYI, enterprise customers are able to order a new type of content as custom work (additional charges will be applied).